Roll-up doors are used for a wide variety of applications. For example, roll-up doors are frequently used to secure the interiors of enclosed storage areas, such as the areas within storage units in a commercial self-storage rental facility.
When used to secure the interior of enclosed storage areas, the roll-up doors are typically made from steel and the doors are provided with a locking apparatus. In the most common applications, such locking apparatuses comprise at least one slidable bolt attached to the door or a strong slide rail. FIG. 1 illustrates such a locking apparatus. The slidable bolt can be alternatively (1) slid in one direction along the slide rail to a “latched position,” wherein the bolt is caused to protrude into a strike plate mounted on the door frame (to prevent the door from traveling upward) and (2) slid in the opposite direction along the slide rail to an “unlatched position,” wherein the bolt is retracted out of the strike plate (to allow the door to again freely travel upward).
Typically, the slide rail and the slidable bolt each have a padlock retainer portion defining a locking through-hole which is sized and dimensioned to accept a padlock shackle (curved portion). The holes in the padlock retainer portions are located so that, when the bolt is slid to the latched position, the holes are aligned with one another such that a padlock shackle can be placed and secured within both holes to lock the bolt within the latched position (as illustrated in FIG. 2).
It is also common that both the slide rail and the bolt have an auxiliary hole—termed a manager's overlock hole—which can be used by the manager of a facility employing the roll-up door to lock the door in the latched position (for example, if rent is overdue). The manager's overlock hole can also be used to retain the padlock on the roll-up door when the bolt is in the unlatched position. This design seems to provide the user with a convenient place to store the padlock when it is not being used, such as immediately after the user unlocks the padlock and slides the bolt to the unlatched position in preparation for opening the roll-up door. The problem with this design, however, is that, if the user forgets to remove the padlock from the manager's overlock hole before the roll-up door is opened, the padlock will be carried upwards as the roll-up door is opened and strike the upper horizontal portion of the door frame. This illustrated in FIG. 3. Because roll-up doors are typically heavy and carry considerable momentum, such striking of the door frame can cause significant damage to the door frame, to the latch assembly and/or to the roll-up door. If the door frame is made of steel or other heavy material, the striking of the door frame with the padlock can rip the latch assembly off of the roll-up door.
Accordingly, there is a need for a padlock retaining device that addresses the problem often encountered with the use of roll-up doors.